Titanium is often used in implantable medical devices because it is biocompatible. Although titanium is generally stable in implantable medical devices, it is sometimes desired to use titanium in aggressive chemical environments, for example as components within an electrical power source of the implantable medical device, such as within an electrochemical cell, also referred to herein as a cell or a battery. In some cases, the electrolyte compounds used to create an electrochemical cell can be corrosive to titanium components. For example, a fluorine-containing electrolyte may corrode a titanium current collector that is used to mechanically support and provide electrical contact to a battery cathode. The fluorine may react with the titanium to form compounds comprising fluorine and titanium that are electrically insulating so that electrical contact between the current collector and the cathode material may become degraded. Over time, as more and more of the titanium is corroded, the overall electrical impedance of the battery increases over the life of the battery so that the battery provides less power over time to the implantable medical device.